Day/Night

Must transition smoothly between day and night, affecting light direction, intensity and colour and altering the skybox.

Seasons

Must transition smoothly between seasons, affecting many aspects, including but not limited to:

Foliage colour

Fall and growth of leaves on trees and their gather and decay on the ground.

Weather and temperature probabilities and ranges

Weather

The weather must cycle between at least the following types of weather

Clear day

Rain

Snow

Fog

Weather types are to be implemented through particle effects and post-processing and must affect the shaders used in the environment as well as lighting. These same systems must also express temperature and wind speed visually.

Skybox

Features:

Sun and moon, which move through the sky

Several types of clouds which form and disperse and move through the sky

The skybox must accommodate all previously mentioned systems as follows: